How would you add a subscript to one particular word of a title in R? For example, suppose the title is "A_2 and B_2." How would you add these two subscripts? I know that expression("A"[2]) and expression("B"[2]) individually add subscripts to these letters.
You do not need paste (or quotes for that matter) at all:
expression( A[2]~and~B[2] )
Test:
plot(1,1, main=expression( A[2]~and~B[2] ) )
The syntactic principle is that tildes (which creates a space) and asterisks (non-space plotmath separator) are used to separate items and that no quotes are needed unless you are using a plotmath function name .... such as wanting the word "paste" or "sqrt" to appear in the displayed version of the expression.
Just paste them together:
expression(paste("A"[2], " and B"[2])
Related
Specifying text in a base R plot() with formatting such as italics / bold font / newline usually involves one or more of the following functions:
paste()
expression()
atop()
substitute()
italic()
Is there an intuitive explanation for the differences between these functions and when best to apply them?
What you're referring to is the plotmath syntax.
To start off, let's make it clear that for a plotmath expression to be interpreted as such, you tell R it's an "expression" and that is why you need expression().
So any time you want to use special symbols or formatting, like italic() and atop(), it's actually a part of plotmath and so you need to wrap it in an expression. eg:
plot(0, main = expression(atop(over,italic(under))))
If you've tried out ?italic or ?atop, you've probably noticed it takes you straight to the plotmath manual page, where a bunch of other functions are listed.
What about substitute() ? Well in my previous example, you'll notice I used strings directly to write 'over' and 'under', without putting them within quotes. This is because of the special expression() environment.
So if you need to put whatever is inside a variable in your text (rather than the variable name) then you put your expression inside a substitute() and give it the arguments. eg:
plot(0, main = substitute(atop(oo,italic(under))), list(oo='over2')))
Note that we don't put substitute around the expression block but replace it entirely.
Finally, where does paste() come in all this ? Well, paste is the glue (pun intended) with any text not dealt with by plotmath.
So if you need text before or after math symbols (or formatted text), you paste() things together within the expression (or substitute) environment. eg :
plot(0, main = substitute(paste("b4", atop(oo,italic(under)), aft),
list(oo='over', aft = 'after3')))
As before, if you want to paste the content of a variable, you need substitute.
And Voilà that's most of the plotmath you'll ever need!
For any other symbols, or functions, have look at ?plotmath
In the output of the following code,
curve((1+exp(-1*x))^-1,
xlim=c(-10,10),ylim=c(0,1),
main="Logistic function",xlab=expression ("x"[t-d]),
ylab=expression ("G"("x"[t-d],gamma,c)))
In the y-axis label, how to place a semi-colon in between immediately before the gamma instead of a comma?
In this case you just need to think of the semicolon as text rather than a special character you can do
ylab=expression ("G"("x"[t-d]~";"~gamma,c))
or you can use * rather than ~ if you want less space.
I would like to know how to accommodate more than two types of quotes in a same row in R. Let´s say that I want to print:
'first-quote-type1 "first-quote-type2 "second-quote-type2
'sencond-quote-type1
Using one quote in the beginning and one in the end we have:
print("'first-quote-type1 "first-quote-type2 "second-quote-type2 'sencond-quote-type1")
Error: unexpected symbol in "print("'first-quote-type1 "first"
I tried to include triple quotes as required in Python in this cases:
print(''''first-quote-type1 "first-quote-type2 "second-quote-type2 'sencond-quote-type1''')
print("""'first-quote-type1 "first-quote-type2 "second-quote-type2 'sencond-quote-type1""")
However, I also got a similar error. Some idea how to make this syntax work in R?
To use a quote within a quote you can escape the quote character with a backslash
print("the man said \"hello\"")
However, the print function in R will always escape character.
To not show the escaped character use cat() instead
so...
cat("the man said \"hello\"") will return
the man said "hello"
is it possible to indent output in R?
e.g.
cat("text1\n")
indent.switch(indent=4)
cat("random text\n")
print("another random text")
indent.switch(indent=0)
cat("text2\n")
resulting in
text1
random text
another random text
text2
I searched for this a few months ago, found nothing and am now searching again.
My current idea is to "overwrite" (I forgot the special term) the functions cat and/or print with an additional argument like:
cat("random text", indent=4)
Only I'm stuck with this and I dont like this procedure very much.
Any ideas?
Edit:
I should be more particular, nevertheless thank you for the \t (omg, i totally forgot this -.-) and that I can format it inside cat.
The given solutions work, but only solve my second-choice-path.
A switch as shown in my first codeexample does not exist I suppose?
My problem is that I have parts of a bigger program which have multiple subscripts, and the output of each subscript should be indented. This is absolutely possible with the "\t" or just blanks inside cat() but has to be done in every command, which I dont like very much.
Solution
I used Chris C's code and extended it in a very easy way. (Thank you very much Chris!)
define.catt <- function(ntab = NULL, nspace=NULL){
catt <- function(input = NULL){
if(!is.null(ntab)) cat(paste0(paste(rep("\t", ntab), collapse = ""), input))
if(!is.null(nspace)) cat(paste0(paste(rep(" ", nspace), collapse = ""), input))
if(is.null(ntab) && is.null(nspace)) cat(input)
}
return(catt)
}
The same way you used \n to print a newline, you can use \t to print a tab.
E.g.
cat("Parent level \n \t Child level \n \t \t Double Child \n \t Child \n Parent level")
Evaluates to
Parent level
Child level
Double Child
Child
Parent level
As an alternative, you can create a derivative of cat called catt and alter options depending on the script. For example.
define.catt <- function(ntab = NULL){
catt <- function(input = NULL){
cat(paste0(paste(rep("\t", ntab), collapse = ""), input))
}
return(catt)
}
You would then set catt with however many tabs you wanted by
catt <- define.catt(ntab = 1)
catt("hi")
hi
catt <- define.catt(ntab = 2)
catt("hi")
hi
And just use catt() instead of cat().
You may consider the very versatile function capture.output(...), which evaluates the '...' list of expressions provided as main input arguments, and stores the text output (as if it would be displayed in the console) into a character vector instead. Then, you simply have to modify the strings as desired: here you want to add some leading spaces to each string. Finally, you write the strings to the console.
These can be done all in one line of nested calls. For example:
writeLines(paste(" ", capture.output(print(head(iris))), sep=""))
I therefore recommend you all to read the help of the capture.output function, and then try to use it for various purposes. Indeed, since the main input has the usual flexibility of the '...' list-like structure, you are free to include, for instance, a call to one home-made function, and thus do almost anything. As for indentation, that is simply done with paste function, once the former has done its magic.
I would like to have the title for the plot in two lines, but this does not work, why? and how can I make it work?
CVal<-1
SumEpsVal<-2
plot(1:10, main=bquote(paste("C=", .(CVal), " \n ", sum(xi), "=", .(SumEpsVal) )))
This here works:
plot(1:10, main=paste("C=1", "\n", "SumXi=2"))
I guess bquote makes something wrong... (look up ?bquote)
I tried to change environment in bqoute (the where-argument) but I don't know which environment to take.
BTW:
plot(1:10, main=bquote(paste("C=", .(CVal), "bla \n ", sum(xi), "=", .(SumEpsVal) )))
makes something crazy with the "bla".
Personally I would use mtext as already suggested. But if you really want it to be a one-liner, you can "cheat" bquote by using atop:
plot(1:10, main=
bquote(atop(paste("C=",.(CVal)), paste(sum(xi),"=",.(SumEpsVal)))))
It even aligns both lines neatly to the center.
The root issue is that plotmath does not support newlines within the
expressions to be output.
Control characters (e.g. \n) are not interpreted in character strings in plotmath,
unlike normal plotting.
You really need to create and output each line separately.
For example :
Lines <- list(bquote(paste("C=", .(CVal))),
bquote(paste(sum(xi), "=", .(SumEpsVal))))
Now output each line The text in the list is converted to expressions do.call
mtext(do.call(expression, Lines),side=3,line=0:1)
One way to achieve this is to use mtext to add an additional line under the main title as follows:
plot(1:10, main=bquote(paste("C=", .(CVal))))
mtext(bquote(paste(sum(xi), "=", .(SumEpsVal) )),side=3,line=0)
There may be a prettier solution, but perhaps this is enough for your needs.